<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .float{
            height: 200px;
            width: 200px;
            border: 1px solid black;
            background-color: lightgreen;
            float: left;
        }

        .container{
            background-color: lightcoral;
            display: flow-root;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="float"></div>
    </div>
    
    <span>HELLOW</span>
</body>
</html>